新型超硬C5N晶体结构及性能的第一性原理研究(英文)  

Structure and Properties of Novel Superhard C_5N:A First-Principles Study

作　　者：李子鹤 刘超[1] 马梦东 潘益龙 赵智胜 于栋利[1] 何巨龙[1] 

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《高压物理学报》2018年第1期24-32,共9页Chinese Journal of High Pressure Physics

基　　金：National Natural Science Foundation of China(51421091,51332005)

摘　　要：通过使用在晶体结构预测方面成熟的粒子群优化算法,提出了6种化学计量比为5∶1的氮化碳新相。采用基于密度泛函理论的第一性原理计算研究它们的结构、稳定性、机械性能和电子性质。计算结果表明,在提出的6种结构中,P62m-C_5N是能量最稳定的。弹性常数和声子谱计算表明,这些结构在0GPa时是机械稳定和动力学稳定的。电子计算显示,I4_1-C_5N是金属性的,而其他5种结构是半导体。维氏硬度计算表明,除I4_1-C_5N外,其余氮化碳都为超硬材料。通过形成焓计算,分析认为这6种结构能在目前实验所能达到的高压下合成(19~83GPa)。By using the developed particle swarm optimization algorithm on the crystal structural prediction,we proposed 6 novel carbon nitride phases with a 5∶1stoichiometry.Their structures,stability,mechanical and electronic properties were investigated by first-principle calculations with the density functional theory.Our calculations indicate that P62 m-C_5N is energetically favorable in the 6structures.Both elastic constants and phonon-dispersion calculations show that these structures remain mechanically and dynamically stable at 0GPa.Electronic calculations indicate that I4_1-C_5N is metallic while the other 5 are semiconductive.The Vickers hardness shows that all the 6structures are superhard materials except for I4_1-C_5N.Formation enthalpy calculations suggest that these 6 structures can be synthesized at attainable high pressures（19-83GPa）.

关 键 词：氮化碳 第一性原理计算 超硬 高剪切强度 

分 类 号：O481.1[理学—固体物理] O482.1[理学—物理]